problem with multiplayer in cso

hello, ive searched various forums but found no other thread addressing my problem. im on 3.03 OE-A, i dumped Virtua Tennis from a umd using fastloader and converted it into a .cso using UMDGen v4.00. it loads and plays fine, however when i try to adhoc with another psp, it always disconnects and returns me to the main menu at a certain screen just before we actually play. i have a umd in the drive, haven't tried adhoc with any other games yet.

is it possible that compressing the iso to cso might have ripped out the multiplayer function? or that playing without the umd removes the ability to multiplay.. anyone able to shed some light on this? many thanks in advance.

okay practically none of my games work compressed in adhoc, titles include tennis, gta:lcs, nfs, pes5.. they work in iso tho. is it just the games, or can i use custom ripkits to reduce the size but still play adhoc?